The present invention relates to a process for preparing a polysaccharide-based extract from Ganoderma lucidum or Ganoderma tsugae. Particularly, this invention relates to a use of the polysaccharide-based extract of Ganoderma herbal material as an orally active medicinal product which has immunopotentiating and antitumoral effects.
Polysaccharide-based extracts of Ganoderma lucidum or Ganoderma tsugae have been studied for years for their medicinal effects in immunopotenciation and antitumoral activity. For example, in Chemical and Pharmaceutical Bulletin. 29(12): 3611-6, 1981 December, a water-soluble antitumor polysaccharide of Ganoderma lucidum has been studied as to its structure. In Anticancer Research 12(4): 1211-5, 1992 July-August, the effect of Ganoderma lucidum on induction of differentiation in leukemic U937 cells has been discussed. In Japanese Journal of Pharmacology, 59(2):171-6, 1992 June, water-soluble extract of Ganoderma tsugae is indicated to possess an enhanced spleenic natural killer cell activity, and a desirable effect in serum interferon production. It was also reported in Bioscience, Biotechnology and Biochemistry, 57(6):894-900, 1993 June, that the fruiting body of Ganodernma tsugae, the Chinese mushroom Songshan Lingzhi, was subjected to the systemic treating process, i.e. extraction, fractionation, and purification, to obtain polysaccharides which have antitumoral activity. Other studies concerning water-soluble polysaccharides extracted from Ganoderma lucidum or Ganoderma tsugae can be found in Bioscience, Biotechnology and Biochemistry, 58(7): 1202-5, 1994 July; in International Journal of Cancer, 70(6):699-705, Mar. 17, 1997; and in Biological and Pharmaceutical Bulletin, 20(4):417-20, 1997 April. It might be due to the fact that most of the water-soluble polysaccharides as reported above, which were investigated as to the antitumoral and immunomodulating activities, have been extracted in the presence of sodium hydroxide solution, no significant effectiveness in antitumoral and immunomodulating activities have been reported when the water-soluble polysaccharides were administered via alimentary route. All the reports teaching and demonstrating the antitumoral and immunomodulating effects of water-soluble polysaccharides extracted from Ganoderma lucidum or Ganoderma tsugae were based on the effects exhibited by the intake of ganoderma extract via a parenteral route.
It is believed that the presence of sodium hydroxide solution in the extraction of polysaccharide gives rise to the smaller dimension of the polysaccharide molecules in the resultant extract. The polysaccharide molecules of smaller dimension in the ganoderma extract of the prior methods evidently account for the unavailability in reporting the antitumoral and immunomodulating effectiveness of the ganoderma extract when the latter is administered orally.
U.S. Pat. No. 5,721,134 issued to Kwon Hseng Lee et al., taught a proteoglycan G 009 which was extracted from Ganoderma lucidum IY 009, and which possesses antitumoral and immunostimulating effects. The demonstration of such effects is also based on the dosage intake via a parenteral route.
It is an object of this invention to provide a process for preparing a polysaccharide-based extract from Ganoderma lucidum or Ganoderma tsugae which can be used in an orally active medicinal product having antitumoral and immunopotentiating effects.
It is an another object of this invention to provide a pharmaceutical composition manufactured by the process according to the present invention. In the experiments performed in this invention, the inventor unexpectedly found that said pharmaceutical composition can be orally administered while retaining the desired activities in antitumoral and immunopotentiating effects.
In accordance with this invention, the process for preparing a polysaccharide-based extract consists essentially the steps of:
(1) subjecting a raw ganoderma herbal material to an alcohol treatment to remove a major portion of non-polysaccharide ingredients to obtain a polysaccharide-rich product;
(2) using water of an elevated temperature as an extracting agent for the polysaccharide-rich product to obtain a supernatant solution; and
(3) adding an alcohol into the supernatant solution to precipitate the polysaccharide-based extract.